Pump piston



Aug. 25, E. KlBELE PUMP PISTON Filed D80. 11. 1928 v dttozuu;

5 woe; m 3 f Patented Aug. 25, 1931 UNITED STATES PATENT OFFICEll'U'G-ENIEI KIBELE, OF SAN ANTONIO, TEXAS; EUGENIA SCHROEDER, EXEGUTBIXOF 0 SAID EUGENE KIBELE, DECEASED rum? nsron Application filed December11, 1928. Serial No. 325,298.

It is also an object of my invention to arrange a piston in such amanner that each of the parts may be readily replaced, but will at thesame time present a rigid piston capable of prolonged service.

Another object of my invention is to arrange the piston ring upon thehub and having a stabilizer member to firmly support the piston ring.

Another object is to so construct the portions of the piston that aminimum of material will be used as compared with the service which thepiston will render.

Still another object is to construct the head of the piston body with aplurality of serrations to contact the piston ring in such a manner thatthe ring will be mechanically expanded to contact with the cylinderwall.

Other and further objects of my invention will be readily apparent tothose skilled in the art to which my invention appertains when thefollowing description is considered in connection with the drawings,wherein:

Fig. 1 is a central vertical section of one gr form of my improvedpiston showing the several parts clamped on the piston rod in operativeposition in the pump cylinder.

Fig. 2 is a View similar to Fig. 1 but showing a slightly modified formwhich the invention may assume.

Fig. 3 is a detailed view of a follower member in position in the pistonring and showing the form which the serrations may take.

Fi 4 is a sectional view in reduced size showing the shape of thepacking rings as they are free of the piston.

By having reference toFig. 1 'the pump cylinder or liner has'beenindicated by the numeral 1. The usual pump rod or piston rod is shown at2 and is slightly tapered to receive the piston body 3 which serves toretain the piston ring indicated generally at 4. The piston body 3comprisesa body portion or hub 6 and a cross head 5 which is formed withan annular flange 7. The head 5 has a central bevel 8 about the rod2 andhas a face 9 which is perpendicular to the path of movement of the rod2. The periphery of the head 5 is inclined toward the end of the rod 2to form an edge indicated at '10 and mesh with the rim 13 of the innerside of the head 5.

This rim is spaced somewhat from the sleeve 6 so that a groove 12 isformed for a purpose which will be later described.

The body 6 has considerable length and extends almost to the end of therod 2 and is adapted to receive the follower member 18 which is in theform of a cap member which fits over the rod 2 and has a flange whichoverlies the end of the body 6. This flange is similar in contour to thehead 5 and has a perpendicular face 20, a peripheral edge 21, a rim 23and a groove 22 which are similar to the corresponding parts of the head5. The nut 19 is threaded onto the rod 2 and serves as a means ofclamping the hub and follower member together against the packing ring.

The piston ring in this modification is shown as composed of two annularsections, such as 25. Each of these sections has an inner circular face31 which slides closely onto the body 6. Perpendicular to this face 31is a lip 27 which is adapted to seat in the oove 12 or 22. Anindentation 28 merges with the lip 27 and receives the rims 13 or 23.From the indentation 28 the ring curves outwardly and is flared tocontact the periphery 10 of the head and terminates in a skirt portion29. The outer surface 30 of the rin when in position in the cylinder isapproximately concentric with the inner surface 31. The free shape ofthe outer surface is slightly concave from end-to end with the centralportion smaller than the bore of the cylinder. The skirt 25 is made witha slightly larger diameter than the bore of the cylinder in order thatthere may be some initial pressure exerted against the walls of the 10cylinder. This increased diameter of the skirt does not prevent easyassembly. The action of the compressible material in the ring under bothmechanical and hydraulic tension is described later. 'This surface 30 isadapted to contact the cylinder wall as shown in the drawings. Each ofthe ring members has on the side opposite the indentation 28 an annularcut out portion 33 hav ing a face 32 which leaves a ridge 34 on theouter surface 30. The two cavities 33 when the piston is assembled forman annular space adapted to receive a stablizer member 35.

' This member is in the form of a ring or disc which slides onto thesleeve member 6 and is preferably tapered inwardly so that the widestportion is at its periphery.

The piston of my invention is adapted for use in what is known as adouble acting pump in that a working stroke is accomplished in eachdirection of the piston- Due to the type of operation the piston issubjected to a hydraulic pressure on the working stroke which tends toforce the skirt 29 against the cylinder 1, forming a seal and-preventingthe passage of fluid, but on the return stroke it is subjected tosuction in drawing the charge into the cylinder, and this suction tendsto drafiv the skirt 29 away from the cylinder wa In constructing thispiston, so that it may best serve the function required, the lip andgroove arrangement of the hub and ring serves to firmly clamp the face31 against the body 6. As the rims 13 and 23 seat in the grooves of thering'and the inclined faces 10 and 21 contact with the skirt 29 axialpressure is exerted upon the ring. Axial pressure tends to compress theinner portion ofv ring 25 and hold it firmly in place between rims 13and 23 and the stabilizer member 35 and proximate points 43 and 44. Theamount of said expansion is according to precalculated limits and issuch that the diameter of the ring between these points is increased tothe desired running size after the piston is; assembled in the cylinder.This axially applied pressure, together with the radial resultant of thehydraulic pressure exerted on skirt 29 creates a radially directedmovement of the resilient material whichv acts as a seal on cylinder 1against any hydraulic force With the above'construction it will bereadily apparent that I may manufacture the piston rings ofsubstantially the same or smaller in size than the cylinder in whichthey are to operate so that they may be readily inserted in thecylinder. The follower plate 18 and nut 19 are then placed in positionand as the nut 19 is tightened the clamping action distorts the pistonring expanding it radially so that a firm and positive seal is obtainedwith the cylinder wall. I therefore rely upon the inherent resiliency ofthe piston ring material to obtain the fluid seal of the piston.

In Fig. 3 I have shown the follower plate as formed with a plurality ofserrations 15 on the periphery 21. These serrations are of greatestdepth at the outer face and gradually merge with the periphery 21 as therim 23 is reached. The inner surface of the piston ring at 16 ispreferably smooth and as the follower plate is drawn up a portion 17 isforced into each one of the serrations. In this manner small particlesof grit and sand are prevented from entering between the metal and thepiston ring. These serrations also aid in distorting the piston ring inthe clamping actioneffected. Due to resilient material used in rings 25and the more pliable construction embodied in the skirt 29, it isobvious that it is entirely practical to run this piston in a cylinder,the walls' of which are not parallel to the axis of the piston rod whichcondition may and does exist.

It is to be understood that the piston body, hub and follower plate aswell as the stabilizer member are made of metal, but the piston ring maybe made of any suitable resilient composition such as rubber..

The piston shown in Fig. 2 is similar in its action in so far as thepiston ring and head are concerned, is identical with the disclosure inFig. 1. The body sleeve 6 of Fig. 1, however, has been somewhatshortened and -is indicated at 6. The follower member 41 has been formedwith a short sleeve 40 which is similar to the sleeve 6. The sleeves 6'and 40 combined are not equal to the width of the piston, but areadapted to receive between them the stabilizer plate 35 which is similarto the stabilizer plate in Fig. 1 except that the central openingtherein is only of such size as to slide upon the piston rod 2. Thesleeve 40 has a cut out cavity 42 so that it will not bind upon the rod'2.

Ill

With the construction of this embodiment v the stabilizer plate 35 isfirmly clamped between the head and the follower plate so that each ofthe piston rings 25 is individually distorted so that the wear on eachone will not be compensated for by a movement or yielding of the otherring such as is possible in the embodiment of Fig. 1.

It is to be understood that the serrations 15 can be made on either thehead or the follower plate or either of the embodiments which I haveshown.

While I have described two embodiments which my improved piston mayassume, I do not desire to be limited to the exact contour shown exceptas specifically stated by the claims herein.

Having described my invention what I desire to secure by Letters Patentis:

1. A pump piston including an approximately cylindrical body, a radialflange at one end and a follower plate at'the other end, means to clampsaid follower plate slidably upon said body, the peripheral surfaces ofsaid flange and plate being tapered inwardly, a packing ring on saidbody between said flange and plate, and lips on said packing ring curvedoutwardly to overlie said flange and plate and tobe compressed outwardlythereby to force said lips more positively against the cylinder. I

2. A pump piston including an approximately cylindrical body,- a radialflange at one end and a follower plate at the other end,

means to clamp said follower plate slidably upon said body, theperipheral surfaces of said flange and plate being tapered inwardly, apacking ring on said body between said flange and plate, and lips onsaid packing ring curved outwardly to overlie said flange and plate andto be compressed outwardly thereby to force said lips more positivelyagainst the cylinder, said packing ring being transversely divided and astabilizer plate midway of the length thereof.

3. A pump piston including an approximately cylindrical body, a radialflange at one end and a follower plate at the other end, means to clampsaid follower plate slidably upon said body, the peripheral surfaces ofsaid flange and plate being tapered inwardly, a packing ring on saidbody between said flange and plate, and lips on said packing ring curvedoutwardly to overlie said flange and plate and to be compressedoutwardly thereby to force said lips more positively against thecylinder, said follo wer plate being serrated on its outer edge for thepurpose described.

In testimony signature this 1928.

whereof I hereunto aflix my 7th day of December A. D.

EUGENE KIBELE.

